Policy-based key recovery

US10263775B2 · kind B2 · utility

Assignee

• MICROSOFT TECHNOLOGY LICENSING, LLC · US

Inventors

• Srinath Setty · Redmond, US
• Ramarathnam Venkatesan · Redmond, US
• Brant Lee Zwiefel · Mill Creek, US
• Nishanth Chandran · Bengaluru, IN
• Satyanarayana V. Lokam · Bengaluru, IN
• Jonathan Lee · Brooklyn, US
• Sharmila Deva Selvis · Chennai, IN

Key dates

• Filing date: Jun 23, 2017
• Grant date: Apr 16, 2019
• Expiry date: Oct 6, 2037

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L2463/062
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

A device establishes a key recovery policy and generates a key that is protected based on the key recovery policy. The key recovery policy indicates which combinations of other entities can recover the protected key. The device generates different shares of the protected key, each share being a value that, in combination with the other share(s), allows the protected key to be recovered. Each share is associated with a particular leaf agent, the device encrypts each share with the public key of the leaf agent associated with the share and provides the encrypted share to a service. When recovery of the protected key is desired, a recovering authority can generate the protected key only if the recovering authority receives decrypted shares from a sufficient one or combination of leaf agents as indicated by the recovery policy.